The idea that Incas once kept carefully chosen women tucked away at this mysterious ruin in the southern Peruvian highlands is one of several romantic notions first advanced by Hiram Bingham, who discovered the site in 1911, that have been treated harshly by recent re-examinations.Long a popular tourist attraction in Peru and one of the world's most spectacular archaeological sites, Machu Picchu over the past decade has become a focal point in a revival of academic interest in Inca culture. Along with the new wave of research, a number of long-cherished ideas are falling.

Tourist guides still tell the "sun virgins" story: how the most beautiful women from all corners of the Inca empire were selected periodically to live in stone cloisters overlooking the Urubama River valley thousands of feet below, there to tend to the needs, religious and otherwise, of the Inca ruler.

Yale historian Bingham based his theory about the presence of a female religious order at Machu Picchu on an examination of skeletal remains he recovered from tombs. Using state-of-the-art technology of the time, the original study indicated that 109 of the 135 skeletons were female.

But a recent Yale study of the remains, using more sophisticated techniques, shows the sex of the skeletons is more evenly balanced. This knocks the underpinnings away from one of Bingham's most titillating conclusions.

"The Virgins of the Sun idea hasn't been taken very seriously in recent years," Yale anthropologist Richard Burger told National Geographic. The re-examination "has dealt a death blow to that theory." Burger is curator of the collection of human bones, pottery, metals and other artifacts found by Bingham.

Much of the current reappraisal of the Incas and one of their most impressive architectural achievements is due to the work of the patriarch of modern Inca studies, John H. Rowe, who recently retired from the University of California, Berkeley.

Besides inspiring a new generation of Inca scholars, Rowe is responsible for many new perceptions now shaking conventional wisdom about the empire that, before the Spanish conquest, covered all of what is now Equador, Peru, Bolivia and northern Chile.

Another Bingham proposition was that Machu Picchu was known to the Spaniards as Vilcabamba, last stronghold of the Inca lords as they retreated from European cavalry, steel and gunpowder. He theorized that a conspiracy of silence among Indians who remained in the old imperial city of Cuzco kept the Spanish from discovering the mountaintop city of white granite.

"If the conquistadors ever saw this wonderful place, some reference to it surely would have been made; yet nothing can be found which clearly refers to the ruins of Machu Picchu," Bingham wrote in 1922.

After years of poring over 16th century Spanish archives in Lima and Cuzco, Rowe disputed that theory in a paper he delivered in Cuzco during the 1986 conference marking the 75th anniversary of Bingham's discovery.

Rowe reported finding in one of the Spanish documents what he believes to be a clear reference to Machu Picchu. "I was able to suggest the name of at least one Spaniard who had probably seen it," he says.

Based on this and other evidence, Rowe thinks Machu Picchu was the royal estate of a powerful emperor, Pachacute Inca Yupanqui, who led the first major expansion of the empire beyond its highland home around Cuzco.

Scientists now believe Machu Picchu was deserted shortly after Pachacute's death In 1471--61 years before the Spanish conquest.

But scholars still agree with one of Bingham's central observations: that Machu Picchu had great religious significance for the Incas, who worshipped thunder and lightning, running water and mountains, as well as the sun.

"I've got caught out there in a few lightning storms," says Inca specialist Margaret MacLean, who is writing a book about Machu Picchu and other Inca sites in the area. "In a torrential downpour, thunder echoes around the whole basin, as if you're in an ampitheater. It's remarkably impressive and seems to embody all the major elements of Inca religion. It's all right there."